The rockets are equipped with a 20 kg warhead that is packed with thousands of steel ball bearings to increase its deadly effect. Incoming rockets are picked up on radar, which sets off air-raid sirens giving residents only 15 to 40 seconds to run for cover before the rockets explode.

One rocket blew up Monday morning in the play yard outside a kindergarten an hour before children usually arrive, damaging the building near the Gaza border but causing no injuries. “That one rocket exploded beside a kindergarten…it’s a miracle that nobody was injured,” Hannah, whose child attends the kindergarten, told Israel’s Reshet Bet Radio. “It’s feelings of fear mixed with anger. I don’t have any security where I live. I can’t give any security to my kids, and that’s the basic thing that a mother has to give to her children.”

Schools within range of the deadly rockets remained closed, with a quarter million students kept home for safety. Some high school students were forced to take their matriculation exams in bomb shelters.

The Iron Dome missile defense system successfully shot down at least five Grad missiles Monday morning, while others were tracked and allowed to explode in sparsely-populated areas. On Sunday, two rockets exploded in the city of Beersheba, one in a schoolyard that sprayed the ball bearings like bullets against the wall of the building. However, there were no injuries as residents in the areas of the blasts had heeded warnings and taken shelter.

Since Friday, Palestinians fired more than 180 rockets and mortars from Gaza, controlled by the Iran-backed Hamas terror organization. At least 11 civilians were wounded in the attacks. An Islamic Jihad spokesman claimed that since Friday his organization had fired 180 rockets, including 80 Grad rockets, Reshet Bet reported.

Terrorists also fired three mortar rounds Monday at the Kerem Shalom border crossing with Gaza, hitting trucks in an aid convoy destined for Gaza but causing no injuries. The crossing is used to transfer goods from Israel into the Gaza Strip and was closed for a short time after the attack, but subsequently reopened. Officials said that over 180 truckloads of goods were transferred to Gaza on Sunday. Over the years terrorists have repeatedly targeted the Israel-Gaza border crossings in attempts to block all contact with Israel.

Since 2001, Palestinian terrorist groups led by Hamas have fired more than 12,000 rockets and mortars at Israeli communities, killing at least 31 people, wounding hundreds more and damaging hundreds of homes.